CBMEM: Tidy up CAR migration

Move the  CAR migration call to arch -specific part of CBMEM init,
it is truly a x86 specific thing.

Change-Id: I715417e54f197b8745e0670d6b900a5660178141
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/7860
Reviewed-by: Aaron Durbin <adurbin@google.com>
Tested-by: build bot (Jenkins)

src/lib/cbmem.c

@@ -242,8 +242,9 @@ int cbmem_recovery(int is_wakeup)
 		cbmem_fail_resume();
 	}
 
+	/* Complete migration to CBMEM. */
 	cbmem_run_init_hooks();
-	car_migrate_variables();
+
 	return !found;
 }